Silyl rotors and amorphous silicon

Abstract Deuteron magnetic resonance is used to observe deuterated rotating silyl SiD 3 groups in plasma-deposited a-Si:D films. Persistence of the rotor signal from 300 K down to less than 2 K, and comparisons with deuterated amorphous carbon, indicate that the silyl rotors do not lie within the amorphous silicon network. Comparisons of spin relaxation times also show that the rotors do not extend into deuterium-filled microvoids. The silyl rotor signals are not observed in the highest-quality a-Si:D and a-Si:D,H samples. It is concluded that SiD 3 rotating groups extend into deuterium-free spaces between microcrystalline surfaces.